Technical Field
The present invention relates to a polymer membrane for separation or concentration of gas, which contains a hybrid nanoporous material, an application thereof, and a manufacturing method thereof.
Background Art
A separation technology using a membrane is generally used in the separation process of liquid and gas because its principle and process are relatively simple and its application range is wide. In the separation technology, recently, a gas separation technology has been mostly studied because it can obtain economic effects, such as energy consumption reduction and operation cost reduction, compared to conventional gas separation methods, such as liquid distillation, extraction, and adsorption. Particularly, a polymer membrane has an advantage of being able to selectively separate a specific gas from a gas mixture according to the difference between permeation rate and dissolution rate of various gas molecules. However, despite such an advantage, currently-known polymer material for membrane does not exceed the line called “upper bound” due to the limitation in permeability and selectivity. Therefore, it is expected that it is difficult for this polymer membrane to surpass the performance of conventional commercially-available membranes as long as the performance of this polymer membrane is not improved. Generally, all polymer materials show a trade-off phenomenon, which is a very typical phenomenon in the field of membrane separation, and in which selectivity decreases with the increase of permeability, whereas selectivity increases with the decrease of permeability.
Recently, in order to solve such problems, many studies for membrane materials have been conducted. Among them, as a polymer membrane, a thermally-rearranged polymer shows a performance exceeding the upper bound in the separation of CO2/CH4 (H. B. Park et al., Science, 2007, 318, 254). Further, in order to overcome the limitations of polymer materials, studies for inorganic membranes using inorganic materials and mixed-matrix membranes (MMMs) using mixtures of polymers and inorganic materials have also been actively conducted.
Meanwhile, sulfur hexafluoride (SF6), although harmless to humans, is a gas for accelerating the global warming, and has been widely used as an insulating material since the 1960s. This gas is a gas to cause an artificial greenhouse effect. Although the usage of this gas was not much, the demand thereof has recently increased. Sulfur hexafluoride (SF6) is a major greenhouse gas together with carbon dioxide, HFCs, and PFCs. Sulfur hexafluoride (SF6) is a greenhouse gas discharged during a semiconductor or LCD process, and the influence of sulfur hexafluoride (SF6) on the global warming leads to 23,900 times that of carbon dioxide (CO2) on the global warming.
Recently, a unit process technology for a recycling technology through a low-concentration gas separation and concentration system for semiconductor and display has been developed. A technology for treating low-density sulfur hexafluoride (SF6) includes the steps of: pretreating a gas discharged at a low concentration (0.5% or lower) by nitrogen dilution after using sulfur hexafluoride (SF6) in etching and cleaning in semiconductor and display industries; concentrating the pretreated gas through adsorption and membrane; and supplying the concentrated gas to a purification and concentration apparatus for producing high-concentration gas (95% or higher). Therefore, this technology is expected to be proposed as a regulation response technology in the fields of semiconductor and display as nation′ major industries because a large amount of SF6 gas discharged at a low concentration is concentrated at a high concentration, so as to finally recycling the SF6 gas.
Under such circumstances, the present inventors have studied in order to manufacture a polymer membrane for gas separation or concentration, which has excellent gas separation performance capable of selectively separating a specific from various gas mixtures or concentrating the specific gas.